Ok, got this passing testes, which I guess is a step in the right direction.

Before changing unique pointers to rcp, we could only use an image once, as soon as we assigned a new image, the old image would get garbage collected. (this is the actual problem we are trying to solve)

This "solves" the problem and  allows us to add images to a cache in wasm, and then cycle through the cache, swapping out the render image to be displayed for a given fileAsset. We can replace images & fonts on the fly this way.

1. overwriting ref & unref in RenderImage, shows that is being reffed and un-reffed constantly (when viewing the attached file with the viewer). Is that expected? doing something similar for Font does not show up the same. I suspect this is related to how we use images when it comes to rendering, just figured i'd check
2. We dont seem to "leak" anything as detectable by our tests, which is good, but our wasm examples show that neither our fonts nor our render images get collected. presumably thats because we would need to manually tell wasm via js that we want to let go of an image?

Also @csmartdalton @umberto-sonnino & @luigi-rosso  it would be great to see what else is concerning.

example file


1506b069c Outofbandcache (#6049)

Co-authored-by: Maxwell Talbot <talbot.maxwell@gmail.com>
18 files changed
tree: f54eb83b6c4d7143e7c3d91afa7518e5e568756b
  1. .github/
  2. .vscode/
  3. build/
  4. cg_renderer/
  5. decoders/
  6. dependencies/
  7. dev/
  8. include/
  9. rivinfo/
  10. skia/
  11. src/
  12. tess/
  13. test/
  14. utils/
  15. viewer/
  16. .dockerignore
  17. .gitignore
  18. .lua-format
  19. .rive_head
  20. build.sh
  21. Dockerfile
  22. Doxyfile
  24. README.md

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Rive hero image

Rive C++ is a runtime library for Rive, a real-time interactive design and animation tool.

The C++ runtime for Rive provides these runtime features:

  • Loading Artboards and their contents from .riv files.
  • Querying LinearAnimations and StateMachines from Artboards.
  • Making changes to Artboard hierarchy (fundamentally same guts used by LinearAnimations and StateMachines) and effienclty solving those changes via Artboard::advance.
  • Abstract Renderer for submitting high level vector path commands with retained path objects to optimize and minimize path re-computation (ultimately up to the concrete rendering implementation).
  • Example concrete renderer written in C++ with Skia. Skia renderer code is in skia/renderer/src/skia_renderer.cpp.

Build System

We use premake5. The Rive dev team primarily works on MacOS. There is some work done by the community to also support Windows and Linux. PRs welcomed for specific platforms you wish to support! We encourage you to use premake as it's highly extensible and configurable for a variety of platforms.


In the rive-cpp directory, run build.sh to debug build and build.sh release for a release build.

If you've put the premake5 executable in the rive-cpp/build folder, you can run it with PATH=.:$PATH ./build.sh

Rive makes use of clang vector builtins, which are, as of 2022, still a work in progress. Please use clang and ensure you have the latest version.

Building skia projects

cd skia/dependencies
./make_skia.sh      // this will invoke get_skia.sh

To build viewer (plus you'll needed CMake installed)



Uses the Catch2 testing framework.

cd dev

In the dev directory, run test.sh to compile and execute the tests.

(if you've installed premake5 in rive-cpp/build, you can run it with PATH=../../build:$PATH ./test.sh)

The tests live in rive/test. To add new tests, create a new xxx_test.cpp file here. The test harness will automatically pick up the new file.

There's a VSCode command provided to run tests from the Tasks: Run Task command palette.

Code Formatting

rive-cpp uses clang-format, you can install it with brew on MacOS: brew install clang-format.

Memory Checks

Note that if you‘re on MacOS you’ll want to install valgrind, which is somewhat complicated these days. This is the easiest solution (please PR a better one when it becomes available).

brew tap LouisBrunner/valgrind
brew install --HEAD LouisBrunner/valgrind/valgrind

You can now run the all the tests through valgrind by running test.sh memory.

Disassembly Explorer

If you want to examine the generated assembly code per cpp file, install Disassembly Explorer in VSCode.

A disassemble task is provided to compile and preview the generated assembly. You can reach it via the Tasks: Run Task command palette or you can bind it to a shortcut by editing your VSCode keybindings.json:

        "key": "cmd+d",
        "command": "workbench.action.tasks.runTask",
        "args": "disassemble"